Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753437AbaBYRQ0 (ORCPT ); Tue, 25 Feb 2014 12:16:26 -0500 Received: from devils.ext.ti.com ([198.47.26.153]:41169 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753296AbaBYRQX (ORCPT ); Tue, 25 Feb 2014 12:16:23 -0500 Message-ID: <530CCFB5.5030205@ti.com> Date: Tue, 25 Feb 2014 09:15:33 -0800 From: Russ Dill Organization: Texas Instruments User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Thomas Gleixner CC: Sebastian Capella , Russell King - ARM Linux , , , , , Andrew Morton , Will Deacon , Robin Holt Subject: Re: [PATCH RFC v1 1/3] ARM: Add irq disabled version of soft_restart. References: <1392774729-3235-1-git-send-email-sebastian.capella@linaro.org> <1392774729-3235-2-git-send-email-sebastian.capella@linaro.org> <20140222102616.GG21483@n2100.arm.linux.org.uk> <20140224231345.10580.62916@capellas-linux> <530C4CAE.5000202@ti.com> In-Reply-To: X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/25/2014 02:27 AM, Thomas Gleixner wrote: > On Mon, 24 Feb 2014, Russ Dill wrote: >> On 02/24/2014 03:13 PM, Sebastian Capella wrote: >>> Quoting Russell King - ARM Linux (2014-02-22 02:26:17) >>>> On Tue, Feb 18, 2014 at 05:52:07PM -0800, Sebastian Capella >>>> wrote: >>>>> From: Russ Dill >>>>> >>>>> This adds the ability to run soft_restart with >>>>> local_irq/fiq_disable already called. This is helpful for >>>>> the hibernation code paths. >>>> >>>> I'd rather keep this simple. There's no problem with calling >>>> soft_restart with interrupts already disabled. >>>> local_irq_disable()/local_fiq_disable() there should be >>>> harmless. >>> >>> Hi Russell, >>> >>> I'm observing a data abort loop when I replace this call: >>> >>> In the local_irq_disable, it ends up calling >>> trace_hardirqs_off (CONFIG_TRACE_IRQFLAGS_SUPPORT is enabled), >>> which calls trace_hardirqs_off_caller which checks >>> lockdep_recursion in the current task, but we've switched to a >>> temporary stack with the call_with_stack, and get_current is >>> returning NULL. This triggers a data abort, which calls >>> trace_hardirqs_off again and so on. >>> >>> Do you have any suggestions here? >>> >>> Thanks, >>> >>> Sebastian >>> >> >> So the alternative is to have a version of the call that calls a >> special no trace version of >> local_irq_disable()/local_fiq_disable(). Which would be >> preferable? Having a noirq version of soft_restart seems much >> simpler to me. > > If you want escape the tracer and in that case you really want it > being on a different stack, use raw_local_irq_* which are not > traced. So it might make sense to change soft_restart to use the raw_local_irq_* calls. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/